The entire disclosure of Japanese Patent Application No. 2000-144886 filed on May 17, 2000 including specification, claims, drawings, and abstract is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a printing plate changing device for supplying a new printing plate to a plate cylinder of a printing press.
2. Description of Related Art
As a conventional printing plate changing device for supplying a new printing plate on a plate cylinder of a printing press, devices disclosed in Japanese Utility Model Registration No.3032484 and Japanese Patent Publication No. Hei8-108525 is known.
In the printing plate holding device disclosed in Japanese Utility Model Registration No. 3032484, a new printing plate can be supplied to a plate cylinder by pivotally releasing a hook for holding the new printing plate in a printing plate supplement frame by an operation unit. In a printing plate holding device disclosed in Japanese Patent Publication No. Hei8-108525, a new printing plate is set into a new printing plate cassette. An end portion of the new printing plate is engaged with a claw member for supporting a rear end of the new printing plate. The claw member for supporting the rear end of the new printing plate is moved by a new printing plate feeding air-cylinder device along a printing plate supplement direction. By pivoting the claw member for supporting the rear end of the new printing plate by a claw releasing cam in order to release the engagement with the end portion of the new printing plate while the claw member is moved, the new printing plate can be supplied to the plate cylinder.
In the printing plate changing device disclosed in Japanese Utility Model Registration No. 3032484, a hook for holding a new printing plate is engaged/released by pivoting an exclusive operation unit. The number of parts becomes large such that a total weight of the device becomes heavy and its cost becomes high. On the other hand, in the printing holding device disclosed in Japanese Patent Publication No. Hei8-108525, an operation for setting a new printing plate is complicated since the new printing plate must be inserted into the cassette for the new printing plate while the claw member for supporting the rear end of the printing plate is operated.
If the printing plate is abnormally attached to a plate cylinder, the abnormally attached printing plate must be released from the corresponding plate cylinder by rotating a plate cylinder in a reverse direction with respect to a printing plate supply direction. The other plate cylinders are reversely rotated in synchronization with the reverse rotation of the plate cylinder. Therefore, to avoid being damaged, a gripped end of a printing plate should be wound on the other plate cylinder during/before an attachment operation in the reverse rotation.
It is an object of the present invention to provide a printing plate change device for supplying a new printing plate to a plate cylinder that comprises a new printing plate releasing means for releasing an end portion of the new printing plate at a downstream side along a new printing plate supplement direction from the plate cylinder.
It is another object to provide in the printing plate change device according to the present invention, the printing plate releasing means releases the end portion from the plate cylinder in the case that the new printing plate is wrongly attached.
It is another object to provide in the printing plate change device according to the present invention, the printing plate change device comprises a new printing plate storing means having a stored portion for storing the new printing plate, wherein the new printing plate releasing means is characterized of moving the new printing plate so as to store the new printing plate in the stored portion of the new printing plate storing means.
It is still another object to provide in the printing plate change device according to the present invention, the new printing plate releasing means comprises a new printing plate engagement member for engaging with the end portion of the new printing plate at an upstream side along a new printing plate supplement direction.
To solve the above problem, in the printing plate changing device according to the present invention, the new printing plate releasing means comprises a new printing plate engagement member movably arranged at the new printing plate storing means and engaging with the end portion of the new printing plate at the upstream side with respect to a new printing plate supplement direction.
To solve the above problem, in the printing plate changing device according to the present invention, the printing plate changing device comprises a new printing plate releasing member provided at a downstream side along a new printing plate storing direction with respect to a stored position at an upstream side of the new printing plate storing means along the new printing plate supplement direction, wherein the new printing plate releasing member backwardly moves the new printing plate engagement member from the stored portion of the new printing plate storing means by moving the new printing plate engagement member toward the downstream side along the new printing plate supplement direction.
To solve the above problem, in the printing plate changing device according to the present invention, the printing plate changing device comprises moving means for moving the new printing plate storing means between an operation position for supplying the new printing plate to the plate cylinder and a shelter position released from the plate cylinder, wherein the new printing plate engagement member is advanced to the stored portion of the new printing plate storing means to engage with an end portion of the new printing plate by moving the new printing plate storing means to the operation position by the moving means, and new printing plate engagement member is movably provided with respect to the new printing plate storing means to backwardly move from the stored portion of the new printing plate storing means by moving the new printing plate engagement member to the shelter position of the new printing plate storing means by the moving means.
To solve the above problem, in the printing plate changing device according to the present invention, the upstream side of the stored portion along the new printing plate supplement direction is located at a location lower than the downstream side of the new printing plate along the new printing plate supplement direction in the case that the new printing plate storing means is in the shelter position, the new printing plate engagement member is pivotally supported on the new printing plate storing means, in the case that the new printing plate storing means is located at the storing position, the new printing engagement member is located at a downstream side along a new printing plate supplement direction with respect to an upstream end of the storing portion of the new printing plate storing means along the new printing plate supplement direction, and a distance between a pivotal point at the stored position of the new printing plate engagement member and the end portion at the upstream side of the stored portion of the new printing plate storing means along the new printing plate supplement direction is longer than a distance between the pivotal point and a front end of the new printing plate engagement member.
To solve the above problem, the printing plate changing device according to the present invention further comprises an energizing member for advancing the new printing plate engagement member toward the stored portion, and a contacting member for backwardly moving the new printing plate engagement member from the stored portion of the new printing plate storing means against force urged by the energizing member by contacting with the new printing plate engagement member.
To solve the above problem, in the printing plate changing device according to the present invention, the new printing plate releasing means moves an end portion of the new printing plate at a downstream side along a new printing plate supplement direction along a substantially radial direction of the plate cylinder.
To solve the above problem, in the printing plate changing device according to the present invention, the new printing plate releasing means includes a swing plate provided near the plate cylinder.
To solve the above problem, the printing plate changing device according to the present invention comprises a discharged printing plate storing means having a stored portion for storing a discharged printing plate discharged from the plate cylinder, wherein the new printing plate releasing means releases an upstream end portion of the discharged printing plate along a discharged printing plate storing direction, which is stored in a stored portion of the discharged printing plate storing means, from the plate cylinder.